In connection with motor vehicles, different types of bearings are utilized for supporting the wheels on respective wheel axles. In heavier commercial vehicles, the rear wheels may be carried on bearings on the rear axle of the vehicle by means of two roller bearings mounted next to each other. Conventionally, these roller bearings are arranged side-by-side so that they bear on each other. The roller bearings are kept together in an unmounted condition by means of a bearing ring, which is substantially annular and arranged on the rear axle.
Within the internal surfaces of the inner races of the bearings (i.e. on the surfaces which are constituted by the inside of the inner races and the outside of the rear axle itself), a thin layer of oil must be supplied for corrosion protection of the bearings and the rear axle. This oil is successively supplied via the interior of the rear axle and is conducted in between the peripheral surface of the rear axle and the inner side of each respective roller bearing. Furthermore, traditionally the roller bearings themselves are lubricated by bearing grease. This bearing grease is applied when assembling the roller bearings and is retained on the bearing rollers and bearing races by means of seals.
In the patent publication WO 97/42425, a known arrangement is provided with a sealing device that is intended to be mounted in connection with a roller bearing on a rear axle of a vehicle. In actual fact, the arrangement is intended for solving a problem that arises as a consequence of a small gap that forms between the inner races of the two roller bearings. This gap entails a risk that the layer of oil present between the inner sides of the roller bearings and the rear axle will penetrate through the gap when the vehicle is running. This problem may be solved by means of the arrangement according to WO 97/42425.
It is also known that a wheel hub for commercial vehicles, for instance according to what is disclosed in WO 97/42425, is designed to facilitate assembly in connection with the manufacturing of the vehicle. A wheel hub is usually dimensioned and designed so that it will remain operable during the entire life of the vehicle, that is, corresponding to a mileage of 800,000 km (approximately 500,000 miles) or more. A precondition for this is that the vehicle is driven according to set regulations and for example is not subjected to a higher load than the guidelines set out for each respective type of vehicle. If a heavy commercial vehicle is frequently subjected to excessively heavy loads or is otherwise driven in an unsuitable way, for example in a difficult environment or under much too hard driving conditions, there is a risk that the wheel hubs and the components making up the wheel hubs may be damaged and need to be repaired or replaced. However, such operations are complicated, whereby damage on components making up the wheel hub often requires replacement of the entire wheel hub, which of course is expensive. This demand for the replacement of an entire wheel hub (that is instead of repairing it) is in particular caused by the requirements for high standards with respect to cleanness, sealing properties and quality of the wheel hub. These standards must be maintained even after such an operation. Individual components of a wheel hub are therefore not always easily replaceable.
It may also be noted that when assembling a wheel hub of a conventional type, the outer ring of the respective bearing is usually mounted first. Then the inner ring is mounted with a conical bearing. This type of assembly requires a very high degree of cleanness so that there is no risk of penetration of impurities and a reduced function of the wheel hub.
In those cases where it is not desired to replace an entire wheel hub but only replace certain components, for instance one of the hub bearings, it is necessary that this can be done in a simple and cost effective manner. Even after the replacement of a certain component it is desirable to maintain high standards with respect to cleanness and quality of the wheel hub.
Hence it may be established that there exists a need for performing repairs of wheel hubs, and in particular for heavy commercial vehicles involving replacement of for instance wheel bearings. A problem that can arise during such an operation in accordance with known prior art is that there is a risk of dirt and impurities entering the wheel hub in connection with a replacement of the wheel bearings. This may in turn cause an operational breakdown that will require further repairs of the wheel hub.